This invention relates to new and useful improvements in slab extruding machines of the type wherein a frame is mounted upon wheels on a pair of rails between which a pallet extends. A hopper is mounted on the frame and feeds concrete or the like downwardly to a set of augers which are rotated by a source of power. These augers pick up the concrete and compress it within a packing chamber to form the slab with longitudinal bores therethrough formed by the augers. The compression of the concrete drives the machine forwardly on the rails with the slab being extruded therebehind.
Conventional machines are of sufficient dimensions to form a slab 6, 8 or more inches in thickness so that there is plenty of room within the augers to provide vibrators in order to assist in the compaction of the concrete.
However, when it is desired to produce a slab having a thickness less than 6 inches (as for example, 4 inches) the augers of necessity have to be of such a small diameter that it is not possible to engage vibrators therewithin.